Air moving device



May 17, 1966 D. D. KINSWORTHY 3,251,540

AIR MOVING DEVICE Filed Deo. 17, 1963 2 Sheets-Sheet 1 INVENTOR. DONALDD. KINSWORTHY ATTORNEYS May 17, 1966 D` D. KINSWORTHY AIR MOVING DEVICE2 Sheets-Sheet 2 Filed Dec. 17, 1963 INVENTOR. KINSWORTHY DONALD D.

ATTORNES United States Patent C 3,251,540 v AIR MOVING DEVICE Donald l).Kinsworthy, Dayton, Ohio, assignor to The Lau Blower Company, Dayton,Ohio, a corporation of (Ehio uned nee. 17, 1963, ser. No. 331,140 1Claim. (Cl. 2311-117) This invention relates to a blower assembly, andparticularly to a blower of the transverse or tangential flow type.

fBlower assemblies which utilize a blower wheel and a cooperatinghousing to draw air radially between the blades on one side of thescroll and force the air outwardly therefrom between the blades at someother point in the blower wheel are termed cross-110W, transverse, ortangential blowers, and for the pu-rposes of discussion herein theseblower wheels will be designated tangential blower wheels. Theadvantages of such a blower include the capability of producing highstatic pressures, and their compact size which enables use in relativelythin heating or cooling units wherein it is not feasible or desirable todraw the air axially into the blower wheel as required in conventionalcentrifugal blower wheels. In a blower unit using a tangential blowerwheel, both the inlet and outlet are substantially tangential to thewheel, whereas in a conventional centrifugal type blower wheel there isan -axial inlet and a radial outlet. The capacity of the blower wheel isthus limited to the size of the inlet which is proportioned to thediameter of the blower wheel, so that a high capacity air conditioningunit requires a com.- paratively thick cabinet. In a tangential blowerwheel the capacity is increased merely by increasing the axial lengththereof with any consequent changevin the thickness of the associatedunit or its cabinet.

However, these tangential blowers are not without serious disadvantages,for example, the relatively simple designs disclosed in the UnitedStates patents of Anderson No. 1,838,169, issued December 29, 1931, No.1,886,- 513, issued November 8, 1932, and No. 1,920,953, issued August8, 1933, never became commercially successful -since their apparentcapacity was low and their performance varied measurably for slightchanges in speed. Several recent developments are disclosed in theUnited States patents to Eck Re. No. 25,236, issued April 2, 1963, andCoester No. 3,033,441, issued May 8, 1962 and Re. 25,409, issued July 2,1963. Each of these designs has a complex housing structure which ishighly sensitive to dimensional changes thus resulting in a veryexpensive blower substantially incapable of low cost mass production.

Accordingly, an important object of this invention is to provide animproved and simplified tangential blower assembly which is not subjectto the aforesaid disadvantages and can be mass produced at a relativelylow cost without any substantial loss in operating efficiency.

Another object of this invention is to provide a blower assembly of thetransverse type wherein the blower is simple in design and easilymanufactured from sheet metal, plastic, or other thin materials, andparticularly to provide such an assembly wherein an efiicient conversionfrom velocity to static pressure is eifected in the housing adjacent theblower wheel so that the length of the outlet portion of the housing isheld to a minimum.

A further object of this invention is to provide a compact tangentialblower wheel assembly which can be constructed in substantially anylength as required to produce the particular volume desired, andparticularly to provide a blower assembly of the aforesaid type whichdoes not require a complex housing having close tolice erances orstructure which induces a vortex inside the blower wheel.

Additional objects and advantages of the invention will be apparent fromthe following description, the accompanying drawings and the appendedclaims.

In the drawings- FIG. 1 is a perspective view of a typical airconditioning unit embodying a tangential blower in accordance with theinvention;

FIG. 2 is a vertical -section View through the air conditioning unitshown in FIG. 1;

FIG. 3 is a perspective illustration of a blower assembly in accordancewith the invention;

FIG. 4 is a front elevation view of the assembly shown in FIG. 1;

FIG. 5 is a sectional view taken essentially along the line 5-5 of FIG.4;

FIG. 6 is an enlarged sectional view of one of the blades of the blowerwheel; and

FIG. 7 is another enlarged sectional view of the rear edge of the outletduct cover.

Referring to the drawings wherein a preferred embodiment of theinvention is shown, FIG. 1 illustrates a typical air conditioning unit10 having an inlet opening 11 in the vertical front wall 12 thereof andan -outlet opening 13 in the top wall 14 thereof. As seen in FIG. 2, atangential blower assembly 15 in accordance with the invention ismounted within the air conditioning unit 10. The air is drawn throughthe grilled inlet opening 11 of the unit 10, through a removable filter17 mounted in the unit immediately ahead of the cooling coils 1S, Afterthe air then passes over the cooling coils 18, it ows into the blowerhousing 20 through the inlet 21, and is drawn between the individualblades 22 and into the interior chamber 24 of the tangential blowerwheel 2S. The blower wheel 25 subsequently forces the air from thechamber 24 into a curved expansion cone 27 created between the blowerwheel 25 and the housing 20 for converting the velocity pressure tostatic pressure. The air then ows through the outlet duct 28 which denesthe large end of the expansion cone 20, over the heating coils 30,through the outlet passageway 31 defined in the air conditioning unit,and then upwardly through the grilled outlet opening 13.

The blower housing 20 is held securely in the unit 10 with the edge 33of its inlet 21 resting on the lower |wall 34 of the housing, and withthe wall 35 of the outlet duct 2S resting on the diagonal support`baffle 36. In addition, the housing 20 may be held positioned incontact with the top and back walls 14 and 37 of the unit 10 by suitablebrackets, not shown, mounted between the unit It) and the blowerassembly 15 so that the housing 2t) is held securely in the airconditioning unit.

The unit 1t) has suitable conventional controls and associated equipmentprovided for selective control of the cooling and heating coils 18 and30, so that the unit 10 can be used as a heating yor cooling unit, ormerely as a ventilation unit if desired. The various walls and supportcomponents of the unit l@ are preferably insulated as shown to insurequiet operation and maximum heating or cooling of the air flowingthrough the blower assembly 15.

FIG. 3 illustrates in more detail the tangential blower assembly 15separated from the unit 1t) including the housing 20 having theelongated blower wheel 25 mounted for rotation therein and driven by themotor 41. The housing 2t) includes aback wall 42 which is volute shapedand extends from the rolled edge 33 substantially directly above theaxis of the blower wheel 25 and to the point 44 (FIG. 5) where thevolute or spiral curve terminates in the integral lower wall 42a of theoutlet duct 28. The

the blower wheel 25 thus define the diffusion cone 27 of l graduallyincreasing width which is an approximation of a logarithmic spiral andextends from a plane through the edge 33 to the -outlet 61, as will beexplained.

The ends of the housing 20 are closed by the fiat end walls 45 and 46Iwhich are divided into the spiral portions 47 and 48 and the outletduct portions 51 and 52, respectively. The spiral portions 47 and 48form the ends of the 'chamber enclosing the blower wheel 25 whereas theoutlet portions 51 and 52 define the side walls of the outlet duct 27.The back wall 42 and the end walls 45 and 46 are secured together by anysubstantially rigid and conventional fluid tight expedients, e.g., lbydeforming the side edges of the back wall 42 over and into contact withthe end walls 45 and 46 and then brazing or spot welding these memberstogether.

An important feature of the invention lies in the position of the flattop wall member 35 which forms the upper Iboundary of the outlet duct 27and which extends between substantially Huid tight and rigid connectionswith the upper edges of the outlet portions 51 and 52 of the side walls45 and 46. The rear edge 55 of this top wall 35 is rolled similarly tothe edge 33, and is also closely spaced from the outer periphery of theblower wheel 25. The front edge 57 of the wall 35 forms the upperperiphery of the outlet opening 58 from the duct 27.

The rectangular inlet 21 is thus defined by the rolled edge 55 of thet-op wall 35, the peripheral edges of the spiral portions 47 and 48, andthe upper edge 33 of the back wall 42. On the other hand, therectangular outlet 58 is defined by the forward edge 57 of the top plate35, the vertical edges 60 and 61 of the outlet portions 51 and 52 of theside Walls, and the front edge 63 of the lower wall 42a.

The elongated blower 'wheel 25 includes a plurality of parallel andcircumferentially disposed blades 22 each of which has its opposite ends64 secured to one of the end plates 65. The blades may be brazed to theend plates,

67 secured rigidly thereto which in turn releasably receives the driveshaft 68 of the motor 41 secured on the outer surface of the side wall45. The right-hand end plate 65 has a similar hub 70 secured thereto forreceiving the support shaft 71 which extends through an opening in theside Wall 46. The right end of the shaft 71 is received and supported bythe bearing member 73, e.g., a roller or other suitable anti-frictionbearing, which is held in place on the side lwall 46 by the retainer 74.

As seen in FIG. 6, the sheet metal blades 22 have smoothly curvedsurfaces, which have a center of curvature at the point 75, andpreferably suicient blade surface to allow the leading edge 76 thereofto have an angle of attack a of about 25 to 30, Whereas the trailingedge 78 extends substantially radially of the blower wheel 25. Thisprovides for maximum scooping action to draw the air into the interiorchamber of the blower, as well as smooth outward flow in the oppositedirection.

Another important feature of thisinvention is that the axial length ofthe housing 20 and blower wheel 25 may be varied to achieve the desiredair output rates. When the axial length of the assembly 15 Ais increasedit may be necessary to reinforce the housing 20 to maintain rigiditythereof, and this can be accomplished by securing `braces to the outsideof the housing since it is undesirable to 4obstruct the smooth innerconfiguration of the housing 20.4 The horizontal edges 33 and 55 of theinlet 21 are rolled to add rigidity to the housing and insure that theprecise configuration of the opening 21 will remain constant. The blowerwheel 25 may be strengthened by adding support disks or bulkheads, forexample, of the types which are used in a double inlet centrifugalblower wheel axially along its length.

As indicated above, the housing 20 and the blower wheel 25 definetherebetween a gradually enlarging cone 27 that starts between the edge33 and the adjacent periphery of the blower wheel 25, and extendsthrough a curved path between the inside surface of the back wall 42 andthe blower wheel 25. This cone continues through the outlet duct 28whose top wall 35 is upwardly tapered, and thus provides for the smoothconversion of velocity pressure to usable static pressure in a compactspace.

As seen in FIG. 7, the rear edge 55 of the top wall 35 is placed asclose as possible to the periphery of the blower wheel 25 withoutcontact therebetween so that the inlet 21 and outlet 58 are effectivelyseparated. In practice it is found that a slight distance must be placedbetween the edge 55 and the blower wheel 25 so that the noise levelcreated thereby lis held -to a minimum. The rolled rear edge 55 alsoaids in reducing the noise created as the blades 22 pass at high speedclose to this edge.

During the operation of this blower assembly the motor 41 rotates theblower wheel 25 at a relatively high speed and in a counterclockwisedirection as viewed in FIG. 5. This rotation causes air to be drawnthrough the inlet 21 between the blades 22 and into the internal chamber24 of the blower wheel 25. The air continues to Iflow across theinternal chamber 24 and then outwardly between the ybla-des 22 oppositethe inlet 21. The air leaving the 'blades enters the curved cone whichextends from the edge 33 and gradually increases in width until itreaches the outlet 58 thus causing a gradual diffusion of the air and ahighly efiicient conversion of the velocity pressure to the staticpressure. Since the curved cone extends entirely around the blower wheel25, except for the inlet 21, the pressure conversion is accomplished bythe time the air reaches the outlet 5S, thus requiring only a shortoutlet duct 28 and consequently a compact and very simple housing.

The housing 20 is constructed .from any material capable of providingthe necessary strength, as well as providing theability to be shapedinto the configuration shown. Thus it is possible to use sheet metal,plastics, or a l combination thereof to construct the housing. While theblower wheel is easily constructed as outlined above, it is Within thescope of the invention to likewise construct it from any suitablematerial capable of being formed into the desired shapes and offulfilling the above described functional requirements.

The invention has provided a tangential or transverse blower assemblywhich is simple in design and is easily mass produced from a variety ofmaterials. The assembly does not require complex structurel in order toinduce a vortex within the blower wheel, and it has been found that thelength of the blower wheel can be varied from a short length to a verylong length. -In addition, the unit can be installed in a minimum ofspace and the inlet and outlet are parallel and do not require the usualninety degrees offset therebetween.

While the form of apparatus herein described constitutes a preferredembodiment of the invention, it is to be understood that the inventionis not limited to this precise form of apparatus, and that changes maybe made therein without departing from the scope of the invention whichis defined in the appended claim.

What is claimed is:

A tangential air moving device of the character described comprising, ahousing having a tangential blower blower wheel, said back wallextending around said wheel at a gradually increasing distance from theaxis of said blower wheel and terminating in a at bottom wall of arectangular unobstructed outlet opening below said blower wheel, saidoutlet opening being spaced approximately 270 from said upper edge ofsaid housing, said housing including at sheet metal closed end wallshaving spiral portions which enclose the ends of said back wall andoutlet portions which define the opposite side walls of said rectangularoutlet opening, a at upper wall of sheet metal on said outlet portion ofsaid side walls clening the upperboundary of said rectangular outletopening, said side walls being the sole support for said blower wheel,lsaid upper wall having an upstream edge closely spaced from the outerperiphery of said blower wheel, said upper edge of said back wall andsaid upstream edge of said upper wall defining a rectangular inletopening of approximately 90 over the circumference of said blower wheel,said blower wheel including a plurality of spaced elongated forwardlycurved blades having an angle of attack with a tangent to said Wheel ofabout 25 and having trailing edge portions which extend radially of saidblower'wheel for smooth flow of air between said blades into and fromsaid blower wheel, said blades dening an unobstructed cylindricalchamber internally of said blower Wheel for the free ow of airtherethrough, a drive motor secured to one of said end walls forrotating said blower wheel at high speed, said housing and blowercooperating -with said outlet opening to dene a curved and unobstructedexpansion chamber which gradually increases in volume and whichcommences substantially at said top edge of said back wall andterminates at said outlet opening for causing a gradual diffusion of thevelocity pressure created by said blower wheel to effect efficientconversion thereof to static pressure.

OTHER REFERENCES German printed application No. 11,074,816, February1960.

SAMUEL LEVINE, Primary Examiner.

HENRY F. RADUAZO, Examiner.

